Various vehicular safety and convenience applications involve sensing or having knowledge of items or objects of interest in or around the vehicle and using such knowledge to take certain actions categorically information, warning, or control related. Such applications may, for example, provide driving environment information and warning to the driver thereby enhancing driver situational awareness and improving opportunity for driver adaptation and intervention in the control of the vehicle (e.g. through braking, throttle and steering), or provide active, semi-active, assistive or adaptive control of vehicle systems based at least in part upon the knowledge of the items or objects of interest.
Depending on the safety and convenience applications, the items or objects of interests may include, for example, other vehicles, obstacles that may pose a collision threat to a moving vehicle, pedestrians, animals, driver's cognizance and state of alertness, location and location related information (such as speed limits), road lanes and other road features, a vehicle's instantaneous stability, traffic signs and signals, ambient lighting and weather conditions, etc. Items or objects of interest knowledge may come from a variety of sensing systems including radar, laser, lidar, ultrasonic, visual or thermal imaging systems, and object recognition based on such imaging systems.
Depending on the safety and convenience applications, the actions taken may include, for example, presenting information and alerts to the driver (e.g. visual, audio or haptic operator warnings), or controlling vehicle systems (e.g. brakes).
Many safety and convenience applications, in information, warning, and control categories, are directional in nature. Direction of the vehicle movement is often used in determining whether application functions should be enabled or disabled by control software. The direction of vehicle movement can be determined with sensors designed for that purpose (such as quadrature phase wheel speed sensors and associated electronic circuitry); however, this approach comes with the increased cost of the sensors. An alternative approach is to use the transmission state to infer the direction of the vehicle movement. In other words, assume forward movement when a forward gear is selected and reverse movement when a reverse gear is selected. While this avoids the cost associated with sensors designed to determine the direction of the vehicle movement, this approach faces challenges when the transmission is in a Neutral state. While functionality may simply be disabled for a transmission Neutral state, the functionalities of the application and the benefits thereof will not be available when the transmission is shifted to Neutral, whether volitionally or not. But there are situations where it is desirable to have the application functionalities and benefits while the transmission is in the Neutral state. Such situations may be more common in vehicles with a manual transmission wherein clutch disengagement and gear transitions are Neutral states. Even in vehicles with an automatic transmission, however, a Neutral state may be purposefully invoked by placing the gear selector into a Neutral position or inadvertently invoked by incorrectly or accidental positioning of the gear selector.
Therefore, it is desirable to have a way to manage a transmission Neutral state such that, for example, vehicular safety and convenience application functionalities can be selectively extended thereto without incurring cost associated with sensors designed to determine the direction of the vehicle movement.